Welding electrode



March 17, 1936. R PK I 2,034,259

WELDING ELECTRODE Original Filed May 11, 1932 INVENTOR W K m 5 BY V 9; 3% W ATTORNEY Patented Mar. 17, 1936 PATENT OFFICE WELDING ELECTRODE Robert K. Hopkins, West Brighton, Staten Island, N. Y., assignor to M. W. Kellogg Company, New York, N. Y., a corporation of Delaware Original application May 11, 1932, Serial No. 610,554. Divided and this application March 15, 1935, Serial No. 11,189

3 Claims. (01. 219-8) This invention relates in general to arc-welding and in particular to apparatus for carrying on as a continuous operation arc-welding in which electrodes, covered with ceram-icor other nonconducting material, are used and is a division of my application Serial No. 610,554, filed May 11, 1932.

Because the coating of the covered welding electrodes does not allow the welding current to pass 10 therethrough to the conducting core it is not possible to use the continuous welding machines I.

designed to handle bare welding electrodes. The present practice is to carry on arc-welding with covered welding electrodes as an intermittent l6 operation by the use of machines which include a current carrying welding head adapted to have fastened thereto a. bare end of the covered welding electrode. The welding head is suitably actuated and controlled to move, together with the go rod or electrode fastened thereto, toward the weld at a speed and in a manner necessary to maintain the desired character of are.

As the welding current is passed to the electrode through a fixed point or fixed points at the 25 end fastened to the welding head of the machine, the prolonged passage of current will excessively heat this end of the electrode and will cause disintegration of the coating. To efilciently use the rod or electrode, it must be kept to such a. length that the greater portion thereof is used before the disintegration of the coating takes place. Due to the present practice of using high amperages the electrode length is necessarily very short. Also, since the welding head cannot be brought too close to thearc, a definite portion of the electrode, usually about must be wasted.

When the maximum allowable portion of the electrode has been used, the arc must be broken and the head retracted to the original position 40 for the removal of the remainder of the used electrode and the fastening thereto of anew electrode. Since the speed of travel of the welding head is the same in both directions of travel at least one-half of the operating time of the ma- 45 chine is taken up in retracting the head and changing electrodes. The interval between the breaking of the arc and starting of -a new electrode is sufliciently long to cause a substantial cooling of the weld, this, coupled to the fact that the metal deposited when a new are is started is generally porous, necessarily causes weak spots along the weld.

This invention contemplates apparatus for carrying on arc-welding with covered welding elec- 55 trodes as a continuous operation uninterrupted for the changing of electrodes and in which the whole of the welding electrode is used.

The invention also contemplates a ceramic or other non-conducting material covered welding electrode of indefinite length made up of an in- 5 definite number of easily joined sections which have small areas of metallic core exposed at points spaced apart along the length through which the welding current may be passed to the core.

The particular nature of the invention, as well as other objects and advantages thereof, will appear most clearly by reference to the accompanying drawing, wherein Figure 1 is a front elevation of an arc welding 5 machine embodying a preferred form of the invention, Y

Figure 2 is a sectional plan view taken on line 22 of Figure 1, showing a current conducting clip encircling the electrode,

Figure 3 is a part sectional view of a preferred form of the welding electrode of the invention, and

Figure 4 is a view similar to Figure 3 with the welding electrode rotated through 90 degrees and showing a different form of connecting means.

, Referring to the drawing:

The welding current generator, the control means therefore, as well as the welding electrode oscillating motor, etc., which per se form no part of this invention, will for the purpose of this description be considered as located in rear of the panel I, with the welding electrode oscillating motor mounted to oscillate panel I. A welding electrode feeding motor 2, the control means of which (not shown) is located at the rear of panel I, is mounted on panel I to oscillate therewith. A grooved wheel 3 is keyed to the shaft of motor 2 and engages a portion of the bottom section of the welding electrode 4. The diametrically opposite portion of welding electrode '4 is engaged by a grooved wheel 5 which is mounted in a pivoted bracket 6. A spring I has one end anchored in a loop at the bottom of bracket 6, its other end 7 being anchored in a loop on a bracket 8, which is bolted or otherwise fastened to panel I. Spring I constantly urges wheel 5 into contact with welding electrode 4 and causes it to bear against wheel 3 with suflicient pressure to prevent slippage. are made of fibre or some such material to prevent damage to the electrode covering as welding electrode 4 passes between them.

The member 9 supports the pivot of bracket 8 and is fastened to an L-shaped guide member I I 55 The contact portions of wheels 3 and 5 vided with the members mounted on shaft erted by spring which is in turn fastened by means of brackets H to panel I to oscillate therewith. The lower portion of guide member I0 is provided with a guide hole through which passes the welding electrode 4 as it approaches the arc.

The welding electrode 4 is made up of an indefinite number of sections, that is to say, as one section is consumed, another is added to the remaining section, or sections, and this procedure continued indefinitely. Each section, as shown in Figures 2-4, comprises a metallic core l3 about which is formed a covering l4 of ceramic or other non-conducting material. One end of each section is provided with the male member l5 and the other end with the female member |6 of a joint forming means. The specific form of joint forming means is not veryimportant.

must, however, be such that the sections may be easily and quickly joined and the joint must be sufficiently strong to support the weight of the welding electrode 4 below the wheels 3 and \i'also it must give a suificiently intimate metal 'to metal contact to allow the passage of the necmsary welding current. In addition, the joint must be such that there is not a substantial gap between the end of one section and the beginning of the next. Figure 3 shows a section proof a threaded joint and Figure 4, a section provided with the members of a dove-tail joint.

To provide for the passage of the welding current from the current supply to the metallic core |3 of the welding electrode 4, portions of the covering l4, equally spaced apart along the length of the electrode 4 are ground out or otherwise removed to expose or substantially expose small areas of the metallic core l3. The voids ll in electrode covering l4 thus produced approximate a frustrum of a cone in shape and as shown in Figures 2-4,expose but a small portion of the electrode core J3 while they allow ready access for contact therewith. The shape of voids l1 may be varied but to produce the result intended; it is essential that but a.small area of the surface of metallic core l3 be exposed and a minimum amount of the'circumference of the covering |4 adjacent the core be broken., If too much of the circumference of core I3 is exposed, a part of covering l4 immediately below the exposed portion will fall into the crater of the weld as the exposed portion comes into the are. .This covering material might later be covered with metal and thus seriously weaken the weld.

In the preferred form of welding electrode 4 voids H are provided at diametrically opposite portions thereof, at points equally spaced apart along the length thereof. This construction is very satisfactory but the invention is not limited thereto as the voids "might be made on one side only or staggered. The invention may be practiced successfully with voids" l1 unequally spaced apart on electrode 4, but no advantage is gained by such uneven spacing and the manufacture of thtee welding electrode is unnecessarily complica d.

edly mounted a disc I9, is supported against rotation in a to panel I.

bracket20 which. in turn is fastened A-circular turntable 2| is rotatably l8 below disc I!) and is held in contact with disc It! by' means of spring 22 which is interposed between nut 23 on shaft l8 and the bottom of turntable 2| The pressure ex- 22 is such that the contiguous faces of disc I9 and turntable 2| are maintained connected to disc l9 by a cable 24. On the bottom of turntable 2| are fastened four cables 25, 2B, 21 and 28 of substantially equal length which terminate respectively in spring clips 29, 30, 3|, and 32. The ends of cables 25, 26, 21 and 28 are spaced 90 degrees apart, adjacent the periphery of turntable 2|. Clips 29, 30, 3| and 32 are adapted to encircle welding electrode 4 and lead current from turntable 2| to the exposed areas of the welding electrode at voids I1. The other side of the welding current source is connected to the work 33 through cable 34.

To start the welding operation, a section of the welding electrode 4 is passed through guides I2 to feed wheel 3 which controls its {further movement. As the first of voids passes panel I on its way to the work 33, the operator of the machine will grasp one of the clips 29, 30, 3| and 32, clip 32 for instance, and turn it through a full turn in the direction opposite to which turntable 2| is to be turned to put a twist in cable 28. After this is done, clip 32 is made to encircle rod 4 and make contact with the area of core l3 exposed by that one of voids I1. When the next void ll passes panel I, the operator will grasp clip 3|, turn it through a complete turn, and pull on it to cause cable 27 to turn turntable 2| through 90 degrees. When this is done, clip 3| is made to encircle welding electrode 4 and make contact with the area of core I3 exposed by the second one of voids When the third and fourth ones of voids I! pass panel |,'the procedure outlined is repeated with with the area of core l3 exposed by the void next adjacent to the one in contact with clip 29. This procedure is repeated as each successive one of the clips and voids approach the hole in guide l0. It is to be noted that the rotation of turntable 2| will twistcables 25, 26, 21 and 28, and if uncompensated for would soon snarl these cables, the undesired snarling is avoided by giving each of cables 25, 26, 21 and 28 the initial twist mentioned. When the upper end of the section of the welding electrode 4 approaches feed wheel 3, a

second section is passed through guides l2 andjoined to the first section.

Four cables 25, 26, 21 and 28 have been shown in the preferred embodiment but the invention is not limited to this number, as three or more can be successfully used. The requirement being that a suflicient number be used so that the welding current is passed to welding electrode 4 at all times through a plurality of points. If this is done, there-is no danger of interrupting the are and sparking upon the making or breaking of contact with the exposed areas of core l3 of electrode 4 completely eliminated.

While a preferred form of the apparatus has been shown and described, it is to be understood that the invention may be embodied in other forms and that various changes may be made in the structural details without departing from the principle of the invention as defined in the appended claims.

I claim:

1. In electric arc-welding, a welding electrode of indefinite length comprising an indefinite number of like sections and means for joining said sections together to form an uninterrupted current path, each of said sections having a reduced threaded portion at one end to serve as an element of the joining means and a bored threaded portion at the other end to serve as the other element of the joining means, and a non-conductive covering for said metallic core extending from the bored end thereof to the beginning of the reduced portion, said covering having diametrically opposite portions thereof removed at regular intervals along its length to expose regularly spaced pairs of small areas of said core, the surface of said non-conducting covering around each of said small areas being concave whereby tangential contact may be made with said exposedareas with minimum removal of said non-conducting covering proximate said exposed areas.

- intervals along its length to expose regularly spaced pairs of small areas of said core, the surface of said non-conducting covering around each of said small areas being concave whereby tangential contact may be made with said exposed areas with a minimum removal of said non-con-' 20 ducting covering proximate said exposed areas.

ROBERT K. HOPKINS. i 

